Recent research has shown that while driving, particularly in conditions of poor visibility, many people suffer an increase in physical and mental stress, they tire more quickly and their reaction-times become notably slower.
This highlights the need for lenses designed specifically for driving that will help improve visual quality, above all in poor light.
Three different problems occur when driving in poor visibility conditions.
Problems linked to greater pupil dilation
The eyes are subject to different stresses when driving at night, in twilight or whenever the light level is low, since the pupils become more dilated, leading to greater perception of aberrations affecting the eyes or any prescription lenses worn, thus drastically reducing the visual quality compared to normal daylight conditions. A typical consequence of this situation is that drivers’ ability to judge distance declines accompanied by a notable increase in stress.
Problems due to frequent rapid eye movements
The need to alternate rapidly and continually between distance and intermediate vision, between the dashboard instruments and the rear-view mirrors, requires a better quality of vision than in normal situations, something that more traditional lens forms are unable to guarantee.
Moreover, from the age of 40-45 years, with the onset of presbyopia, it becomes ever more difficult for the eyes to accommodate to different distances. The most successful solution is to use progressive lenses, although for driving, the intermediate and distance zones must be wider and provide better definition.
Problems caused by glare
When driving in traffic many people find the glare from on-coming car headlights particularly troublesome, especially at sunset or at night when the pupils are more dilated. Modern car headlights, for example those using LED or Xenon bulbs, deliver much higher lighting performance, but cause more optical discomfort that the systems used in the past. This makes it essential for drivers to have adequate glare-protection available to enable them to drive in more comfort and safety.
In order to solve these problems, the optical industry has recently developed new products designed to facilitate visual quality in these light conditions.
The Ital-Lenti research centre has optimised two specific products for these problems, adopting two different approaches, the first relating to the geometry of the lenses and the second to the anti-reflection treatment applied to them.
The result of this research is the production of two different lens forms, one a single-vision and the other a progressive lens. The design of both has been optimised to take account of the pupil dimension in poor light conditions.
SOLUTION ONE – Special lens geometry
The eyes’ ability to dilate the pupils in order to let in more light influences the quality of the images we see, changing the depth of field we perceive.
Both types of product use aspheric and atoric free-form geometry making possible a considerable degree of compensation for the optical aberrations produced when the pupils are dilated and totally correcting any lens aberrations.
In addition, the progressive lens geometry has been specifically optimised for driving, thus providing a design that makes driving with these lenses more comfortable and safer, guaranteeing optimum distance and intermediate vision with none of the lateral interference produced by oblique astigmatism.
These optimised distances facilitate focusing when the vision has to move between the road, the dashboard and the rear-view and side mirrors. This reduces need for horizontal head movements.
SOLUTION TWO – The special anti-reflection coating
For the anti-reflection treatment, Ital-Lenti has developed a new coating optimised for the glare our optical system has to cope with when driving. This coating reflects the majority of the high-energy blue-light wavelengths in the visible spectrum. Modern LED or Xenon light sources produce light emission in the high-energy part of the visible spectrum, specifically at the 450-470nm interval.
The Iron Drive coating makes it possible to attenuate these troublesome light wavelengths which are one of the main causes of glare. The result is an over 70% reduction in the discomfort produced by glare.
These new lenses ensure optimum vision at night or in poor light conditions, but they can also be worn during the day, making them absolutely suitable for everyday use.
What’s more, the coating provides the same quality and maintenance properties as the top-of-the-range Iron treatment.